A smooth, usually painless lump on one side of the vaginal opening is most often a Bartholin cyst — a blocked gland, not an infection on its own. The Bartholin glands sit just inside the vaginal opening and normally produce a small amount of lubricating fluid. When the duct draining one of them gets blocked, fluid backs up and forms a cyst. Most stay small and painless; a smaller number become infected and turn into a painful abscess that needs prompt treatment.
Cyst or abscess — how to tell them apart
| Bartholin cyst | Bartholin abscess | |
|---|---|---|
| Pain | Usually painless or mildly tender | Significant, often throbbing pain |
| Size | Often stays small, pea- to grape-sized | Can enlarge quickly over a day or two |
| Skin over it | Normal colour | Red, warm, sometimes with visible pus |
| Fever | No | Can occur |
| Walking/sitting | Usually comfortable | Often painful |
A cyst that was previously painless and suddenly becomes red, hot, and much more painful has likely become infected and turned into an abscess — that's a reason to be seen promptly rather than waiting it out.
What actually causes it
The exact reason a duct blocks isn't always clear, but it's more common after childbirth, with certain infections (including some sexually transmitted infections, though most Bartholin cysts are not caused by an STI), and simply as a matter of individual anatomy. It is not caused by poor hygiene, and it isn't a sign you've done anything wrong.
When it needs treatment, and what that looks like
- Small, painless cyst: often needs no treatment at all beyond monitoring — warm sitz baths (sitting in a few inches of warm water) several times a day can help some cysts drain and resolve on their own.
- Larger or uncomfortable cyst: your doctor may drain it in a short outpatient procedure, sometimes with a small catheter (a Word catheter) left in place for a few weeks to keep the duct open so it doesn't simply refill.
- Abscess: needs prompt incision and drainage, usually with antibiotics, since it won't resolve with warm baths alone and can become more painful and extensive if left.
- Recurrent cysts: if the same gland keeps blocking repeatedly, your doctor may discuss a marsupialisation procedure, which creates a small permanent opening so fluid can drain rather than pool.
When to see your doctor promptly, not just watch it
- Rapidly increasing pain, redness, or swelling
- Fever or feeling generally unwell
- A lump that keeps recurring in the same spot
- Any lump you're unsure about, especially after age 40 — Bartholin gland swellings are occasionally biopsied in this age group to rule out other causes, since a new gland swelling is less typical at that stage of life
A Bartholin cyst on its own is common, usually painless, and often needs nothing more than warm soaks — but a sudden change to red, hot, and painful is your doctor visit, not your wait-and-watch.
Frequently asked
Will it go away on its own?
Many small, painless Bartholin cysts do resolve without any treatment, particularly with regular warm sitz baths. Larger or persistent ones are more likely to need a drainage procedure.
Is this caused by an STI?
Not usually. Most Bartholin cysts are unrelated to any infection — they're a mechanical blockage of the gland's duct. Your doctor may still check for infection if there are other symptoms, simply to be thorough.
Can I pop it myself?
No — attempting to drain it yourself risks introducing infection and doesn't address the underlying blocked duct, so it's likely to recur. If it needs draining, that should be done by your doctor under sterile conditions.
Will it come back after treatment?
It can, particularly after simple drainage without a catheter left in place. Recurrent cysts are why your doctor may recommend a Word catheter or marsupialisation for a more lasting fix.
Does having a Bartholin cyst affect pregnancy or delivery?
A small, uncomplicated cyst usually doesn't affect a vaginal delivery. If it's large, infected, or close to your due date, mention it to your obstetrician so it can be managed appropriately before labour.